The invention relates generally to apparatus and methods for forming knotted coil springs. In the past, in the manufacture of knotted coil springs, the wire of the coil springs was tempered, if at all, either after the knotting, or after the knotting and subsequent integration into a spring assembly.
Also in the past, the Assignee of this application has sold, for more than one year prior to this application, a coil spring forming, knotting, and tempering machine as shown in the attached brochure filed herewith. The tempering took place after the knotting.
Also in the past, coil springs including end convolutions with parallel portions, such as the central arms 18 shown in U.S. Pat. No. 4,609,186, were initially partially formed by a coil spring forming head or device, were then tempered, and were then formed to include the parallel portions.